jvmtiLocalVariable.cpp

/*******************************************************************************
 * Copyright IBM Corp. and others 1991
 *
 * This program and the accompanying materials are made available under
 * the terms of the Eclipse Public License 2.0 which accompanies this
 * distribution and is available at https://www.eclipse.org/legal/epl-2.0/
 * or the Apache License, Version 2.0 which accompanies this distribution and
 * is available at https://www.apache.org/licenses/LICENSE-2.0.
 *
 * This Source Code may also be made available under the following
 * Secondary Licenses when the conditions for such availability set
 * forth in the Eclipse Public License, v. 2.0 are satisfied: GNU
 * General Public License, version 2 with the GNU Classpath
 * Exception [1] and GNU General Public License, version 2 with the
 * OpenJDK Assembly Exception [2].
 *
 * [1] https://www.gnu.org/software/classpath/license.html
 * [2] https://openjdk.org/legal/assembly-exception.html
 *
 * SPDX-License-Identifier: EPL-2.0 OR Apache-2.0 OR GPL-2.0-only WITH Classpath-exception-2.0 OR GPL-2.0-only WITH OpenJDK-assembly-exception-1.0
 *******************************************************************************/

#include "jvmtiHelpers.h"
#include "jvmti_internal.h"
#include "objhelp.h"

#if JAVA_SPEC_VERSION >= 19
#include "VMHelpers.hpp"
#endif /* JAVA_SPEC_VERSION >= 19 */

extern "C" {

static jvmtiError jvmtiGetOrSetLocal (jvmtiEnv* env, jthread thread, jint depth, jint slot, void* value_ptr, char signature, jboolean isSet, jboolean getLocalInstance);


jvmtiError JNICALL
jvmtiGetLocalInstance(jvmtiEnv* env,
	jthread thread,
	jint depth,
	jobject* value_ptr)
{
	jvmtiError rc;

	Trc_JVMTI_jvmtiGetLocalInstance_Entry(env);

	ENSURE_PHASE_LIVE(env);
	ENSURE_CAPABILITY(env, can_access_local_variables);

	ENSURE_NON_NEGATIVE(depth);
	ENSURE_NON_NULL(value_ptr);

	*value_ptr = NULL;
	rc = jvmtiGetOrSetLocal(env, thread, depth, 0, value_ptr, 'L', FALSE, TRUE);

done:
	TRACE_JVMTI_RETURN(jvmtiGetLocalInstance);
}


jvmtiError JNICALL
jvmtiGetLocalObject(jvmtiEnv* env,
	jthread thread,
	jint depth,
	jint slot,
	jobject* value_ptr)
{
	jvmtiError rc;

	Trc_JVMTI_jvmtiGetLocalObject_Entry(env);

	ENSURE_PHASE_LIVE(env);
	ENSURE_CAPABILITY(env, can_access_local_variables);

	ENSURE_NON_NEGATIVE(depth);
	ENSURE_NON_NULL(value_ptr);

	*value_ptr = NULL;
	rc = jvmtiGetOrSetLocal(env, thread, depth, slot, value_ptr, 'L', FALSE, FALSE);

done:
	TRACE_JVMTI_RETURN(jvmtiGetLocalObject);
}


jvmtiError JNICALL
jvmtiGetLocalInt(jvmtiEnv* env,
	jthread thread,
	jint depth,
	jint slot,
	jint* value_ptr)
{
	jvmtiError rc;

	Trc_JVMTI_jvmtiGetLocalInt_Entry(env);

	ENSURE_PHASE_LIVE(env);
	ENSURE_CAPABILITY(env, can_access_local_variables);

	ENSURE_NON_NEGATIVE(depth);
	ENSURE_NON_NULL(value_ptr);

	*value_ptr = 0;
	rc = jvmtiGetOrSetLocal(env, thread, depth, slot, value_ptr, 'I', FALSE, FALSE);

done:
	TRACE_JVMTI_RETURN(jvmtiGetLocalInt);
}


jvmtiError JNICALL
jvmtiGetLocalLong(jvmtiEnv* env,
	jthread thread,
	jint depth,
	jint slot,
	jlong* value_ptr)
{
	jvmtiError rc;

	Trc_JVMTI_jvmtiGetLocalLong_Entry(env);

	ENSURE_PHASE_LIVE(env);
	ENSURE_CAPABILITY(env, can_access_local_variables);

	ENSURE_NON_NEGATIVE(depth);
	ENSURE_NON_NULL(value_ptr);

	*value_ptr = 0;
	rc = jvmtiGetOrSetLocal(env, thread, depth, slot, value_ptr, 'J', FALSE, FALSE);

done:
	TRACE_JVMTI_RETURN(jvmtiGetLocalLong);
}


jvmtiError JNICALL
jvmtiGetLocalFloat(jvmtiEnv* env,
	jthread thread,
	jint depth,
	jint slot,
	jfloat* value_ptr)
{
	jvmtiError rc;

	Trc_JVMTI_jvmtiGetLocalFloat_Entry(env);

	ENSURE_PHASE_LIVE(env);
	ENSURE_CAPABILITY(env, can_access_local_variables);

	ENSURE_NON_NEGATIVE(depth);
	ENSURE_NON_NULL(value_ptr);

	*(jint*)value_ptr = 0;
	rc = jvmtiGetOrSetLocal(env, thread, depth, slot, value_ptr, 'F', FALSE, FALSE);

done:
	TRACE_JVMTI_RETURN(jvmtiGetLocalFloat);
}


jvmtiError JNICALL
jvmtiGetLocalDouble(jvmtiEnv* env,
	jthread thread,
	jint depth,
	jint slot,
	jdouble* value_ptr)
{
	jvmtiError rc;

	Trc_JVMTI_jvmtiGetLocalDouble_Entry(env);

	ENSURE_PHASE_LIVE(env);
	ENSURE_CAPABILITY(env, can_access_local_variables);

	ENSURE_NON_NEGATIVE(depth);
	ENSURE_NON_NULL(value_ptr);

	*(jlong*)value_ptr = 0;
	rc = jvmtiGetOrSetLocal(env, thread, depth, slot, value_ptr, 'D', FALSE, FALSE);

done:
	TRACE_JVMTI_RETURN(jvmtiGetLocalDouble);
}


jvmtiError JNICALL
jvmtiSetLocalObject(jvmtiEnv* env,
	jthread thread,
	jint depth,
	jint slot,
	jobject value)
{
	jvmtiError rc;

	Trc_JVMTI_jvmtiSetLocalObject_Entry(env);

	ENSURE_PHASE_LIVE(env);
	ENSURE_CAPABILITY(env, can_access_local_variables);

	ENSURE_NON_NEGATIVE(depth);

	rc = jvmtiGetOrSetLocal(env, thread, depth, slot, (j9object_t*) value, 'L', TRUE, FALSE);

done:
	TRACE_JVMTI_RETURN(jvmtiSetLocalObject);
}


jvmtiError JNICALL
jvmtiSetLocalInt(jvmtiEnv* env,
	jthread thread,
	jint depth,
	jint slot,
	jint value)
{
	jvmtiError rc;

	Trc_JVMTI_jvmtiSetLocalInt_Entry(env);

	ENSURE_PHASE_LIVE(env);
	ENSURE_CAPABILITY(env, can_access_local_variables);

	ENSURE_NON_NEGATIVE(depth);

	rc = jvmtiGetOrSetLocal(env, thread, depth, slot, &value, 'I', TRUE, FALSE);

done:
	TRACE_JVMTI_RETURN(jvmtiSetLocalInt);
}


jvmtiError JNICALL
jvmtiSetLocalLong(jvmtiEnv* env,
	jthread thread,
	jint depth,
	jint slot,
	jlong value)
{
	jvmtiError rc;

	Trc_JVMTI_jvmtiSetLocalLong_Entry(env);

	ENSURE_PHASE_LIVE(env);
	ENSURE_CAPABILITY(env, can_access_local_variables);

	ENSURE_NON_NEGATIVE(depth);

	rc = jvmtiGetOrSetLocal(env, thread, depth, slot, &value, 'J', TRUE, FALSE);

done:
	TRACE_JVMTI_RETURN(jvmtiSetLocalLong);
}


jvmtiError JNICALL
jvmtiSetLocalFloat(jvmtiEnv* env,
	jthread thread,
	jint depth,
	jint slot,
	jfloat value)
{
	jvmtiError rc;

	Trc_JVMTI_jvmtiSetLocalFloat_Entry(env);

	ENSURE_PHASE_LIVE(env);
	ENSURE_CAPABILITY(env, can_access_local_variables);

	ENSURE_NON_NEGATIVE(depth);

	rc = jvmtiGetOrSetLocal(env, thread, depth, slot, &value, 'F', TRUE, FALSE);

done:
	TRACE_JVMTI_RETURN(jvmtiSetLocalFloat);
}


jvmtiError JNICALL
jvmtiSetLocalDouble(jvmtiEnv* env,
	jthread thread,
	jint depth,
	jint slot,
	jdouble value)
{
	jvmtiError rc;

	Trc_JVMTI_jvmtiSetLocalDouble_Entry(env);

	ENSURE_PHASE_LIVE(env);
	ENSURE_CAPABILITY(env, can_access_local_variables);

	ENSURE_NON_NEGATIVE(depth);

	rc = jvmtiGetOrSetLocal(env, thread, depth, slot, &value, 'D', TRUE, FALSE);

done:
	TRACE_JVMTI_RETURN(jvmtiSetLocalDouble);
}

#if (defined(J9VM_OPT_DEBUG_INFO_SERVER)) 
static jvmtiError
jvmtiGetOrSetLocal(jvmtiEnv *env,
	jthread thread,
	jint depth,
	jint slot,
	void *value_ptr,
	char signature,
	jboolean isSet,
	jboolean getLocalInstance)
{
	J9JVMTIEnv *j9env = (J9JVMTIEnv *)env;
	J9JavaVM *vm = j9env->vm;
	jvmtiError rc = JVMTI_ERROR_NONE;
	J9VMThread *currentThread = NULL;

	rc = getCurrentVMThread(vm, &currentThread);
	if (JVMTI_ERROR_NONE == rc) {
		J9VMThread *targetThread = NULL;

		vm->internalVMFunctions->internalEnterVMFromJNI(currentThread);
		rc = getVMThread(
				currentThread, thread, &targetThread, JVMTI_ERROR_NONE,
				J9JVMTI_GETVMTHREAD_ERROR_ON_DEAD_THREAD);
		if (rc == JVMTI_ERROR_NONE) {
			J9StackWalkState walkState = {0};
			BOOLEAN objectFetched = FALSE;
			J9VMThread *threadToWalk = targetThread;

#if JAVA_SPEC_VERSION >= 19
			J9VMThread stackThread = {0};
			J9VMEntryLocalStorage els = {0};
			j9object_t threadObject = (NULL == thread) ? currentThread->threadObject : J9_JNI_UNWRAP_REFERENCE(thread);
			J9VMContinuation *continuation = NULL;

#if JAVA_SPEC_VERSION >= 20
			if ((currentThread != targetThread)
			&& (!VM_VMHelpers::isThreadSuspended(currentThread, threadObject))
			) {
				rc = JVMTI_ERROR_THREAD_NOT_SUSPENDED;
				goto release;
			}
#endif /* JAVA_SPEC_VERSION >= 20 */

			continuation = getJ9VMContinuationToWalk(currentThread, targetThread, threadObject);
			if (NULL != continuation) {
				vm->internalVMFunctions->copyFieldsFromContinuation(currentThread, &stackThread, &els, continuation);
				threadToWalk = &stackThread;
			}
#endif /* JAVA_SPEC_VERSION >= 19 */

#if JAVA_SPEC_VERSION < 20
#if JAVA_SPEC_VERSION >= 19
			if (NULL != targetThread)
#endif /* JAVA_SPEC_VERSION >= 19 */
			{
				vm->internalVMFunctions->haltThreadForInspection(currentThread, targetThread);
			}
#endif /* JAVA_SPEC_VERSION < 20 */

			rc = (jvmtiError)(IDATA)findDecompileInfo(currentThread, threadToWalk, (UDATA)depth, &walkState);
			if (JVMTI_ERROR_NONE == rc) {
				UDATA validateRC = 0;
				BOOLEAN slotValid = TRUE;
				UDATA *slotAddress = NULL;
				J9Method *ramMethod = (J9Method *)walkState.userData3;
				U_32 offsetPC = (U_32)(UDATA)walkState.userData4;
				J9ROMMethod *romMethod = J9_ROM_METHOD_FROM_RAM_METHOD(ramMethod);

				if (getLocalInstance) {
					if (OMR_ARE_ANY_BITS_SET(romMethod->modifiers, J9AccStatic)) {
						/* GetLocalInstance illegal on static methods */
						validateRC = J9_SLOT_VALIDATE_ERROR_INVALID_SLOT;
					} else if (OMR_ARE_ANY_BITS_SET(romMethod->modifiers, J9AccNative)) {
						/* GetLocalInstance legal on non-static native methods */
						validateRC = J9_SLOT_VALIDATE_ERROR_NONE;
					} else {
						/* GetLocalInstance == GetLocalObject for non-static, non-native methods */
						validateRC = validateLocalSlot(currentThread, ramMethod, offsetPC, (U_32) slot, signature, TRUE);
					}
				} else {
					validateRC = validateLocalSlot(currentThread, ramMethod, offsetPC, (U_32) slot, signature, TRUE);
				}

				switch (validateRC) {
					case J9_SLOT_VALIDATE_ERROR_LOCAL_MAP_MISMATCH:
						slotValid = FALSE;
						/* intentional fall-through */
					case J9_SLOT_VALIDATE_ERROR_NONE:
						slotAddress = walkState.arg0EA - slot;
#ifdef J9VM_JIT_FULL_SPEED_DEBUG
						if (walkState.jitInfo != NULL) {
							UDATA inlineDepth = (UDATA)walkState.userData2;
							slotAddress = vm->jitConfig->jitLocalSlotAddress(currentThread, &walkState, slot, inlineDepth);
							if (NULL == slotAddress) {
								rc = JVMTI_ERROR_OUT_OF_MEMORY;
								break;
							}
						}
#endif
						if (isSet) {
							if (slotValid) {
								switch(signature) {
									case 'D':
									case 'J':
										memcpy(slotAddress - 1, value_ptr, sizeof(U_64));
										break;
									case 'L':
										/* Perform type check? */
										*((j9object_t *)slotAddress) = (NULL == value_ptr) ? NULL : *((j9object_t *)value_ptr);
										break;
									default:
										*((jint *)slotAddress) = *((jint *)value_ptr);
										break;
								}
#ifdef J9VM_JIT_FULL_SPEED_DEBUG
								if (J9_FSD_ENABLED(vm)) {
									vm->jitConfig->jitStackLocalsModified(currentThread, &walkState);
								}
#endif /* J9VM_JIT_FULL_SPEED_DEBUG */
							}
						} else {
							switch(signature) {
								case 'D':
								case 'J':
									if (slotValid) {
										memcpy(value_ptr, slotAddress - 1, sizeof(U_64));
									} else {
										memset(value_ptr, 0, sizeof(U_64));
									}
									break;
								case 'L':
									/* CMVC 109592 - Must not modify the stack while a thread is halted for inspection - this includes creation of JNI local refs */
									objectFetched = TRUE;
									PUSH_OBJECT_IN_SPECIAL_FRAME(currentThread, slotValid ? *((j9object_t *)slotAddress) : NULL);
									break;
								default:
									*((jint *)value_ptr) = (slotValid ? *((jint *)slotAddress) : 0);
									break;
							}
						}
						break;
					case J9_SLOT_VALIDATE_ERROR_INVALID_SLOT:
						rc = JVMTI_ERROR_INVALID_SLOT;
						break;
					case J9_SLOT_VALIDATE_ERROR_NATIVE_METHOD:
						rc = JVMTI_ERROR_OPAQUE_FRAME;
						break;
					case J9_SLOT_VALIDATE_ERROR_OUT_OF_MEMORY:
						rc = JVMTI_ERROR_OUT_OF_MEMORY;
						break;
					case J9_SLOT_VALIDATE_ERROR_TYPE_MISMATCH:
						rc = JVMTI_ERROR_TYPE_MISMATCH;
						break;
					default:
						rc = JVMTI_ERROR_INTERNAL;
						break;
				}
			} else {
				rc = JVMTI_ERROR_NO_MORE_FRAMES;
			}

#if JAVA_SPEC_VERSION >= 20
release:
#endif /* JAVA_SPEC_VERSION >= 20 */

#if JAVA_SPEC_VERSION < 20
#if JAVA_SPEC_VERSION >= 19
			if (NULL != targetThread)
#endif /* JAVA_SPEC_VERSION >= 19 */
			{
				vm->internalVMFunctions->resumeThreadForInspection(currentThread, targetThread);
			}
#endif /* JAVA_SPEC_VERSION < 20 */

			if (objectFetched) {
				j9object_t obj = POP_OBJECT_IN_SPECIAL_FRAME(currentThread);
				*((jobject *)value_ptr) = vm->internalVMFunctions->j9jni_createLocalRef((JNIEnv *)currentThread, obj);
			}
			releaseVMThread(currentThread, targetThread, thread);
		}
		vm->internalVMFunctions->internalExitVMToJNI(currentThread);
	}

	return rc;
}

#endif /* J9VM_OPT_DEBUG_INFO_SERVER */

} /* extern "C" */